2,858 research outputs found
Electronic structure of the incommensurate compound
We extracted, from strongly-correlated ab-initio calculations, a complete
model for the chain subsystem of the
incommensurate compound. A second neighbor model has been determined as
a function of the fourth crystallographic parameter , for both low and
room temperature crystallographic structures. The analysis of the obtained
model shows the crucial importance of the structural modulations on the
electronic structure through the on-site energies and the magnetic
interactions. The structural distortions are characterized by their long range
effect on the cited parameters that hinder the reliability of analyses such as
BVS. One of the most striking results is the existence of antiferromagnetic
nearest-neighbor interactions for metal-ligand-metal angles of . A
detailed analysis of the electron localization and spin arrangement is
presented as a function of the chain to ladder hole transfer and of the
temperature. The obtained spin arrangement is in agreement with
antiferromagnetic correlations in the chain direction at low temperature
Discriminants, symmetrized graph monomials, and sums of squares
Motivated by the necessities of the invariant theory of binary forms J. J.
Sylvester constructed in 1878 for each graph with possible multiple edges but
without loops its symmetrized graph monomial which is a polynomial in the
vertex labels of the original graph. In the 20-th century this construction was
studied by several authors. We pose the question for which graphs this
polynomial is a non-negative resp. a sum of squares. This problem is motivated
by a recent conjecture of F. Sottile and E. Mukhin on discriminant of the
derivative of a univariate polynomial, and an interesting example of P. and A.
Lax of a graph with 4 edges whose symmetrized graph monomial is non-negative
but not a sum of squares. We present detailed information about symmetrized
graph monomials for graphs with four and six edges, obtained by computer
calculations
Agreement with the Creek and Seminole Nations
55-2Agreements with the Creeks and Seminoles.
[3593] Creek agreement made 27 Sept. 1897; Seminole agreement made
16 Dec. 1897; both provide for allotment
of land, for a restructuring of tribal government, etc.; Dawes Commission.1898-2
Spectrum and decays of kaonic hydrogen
By using the non-relativistic effective Lagrangian approach to bound states,
a complete expression for the isospin-breaking corrections to the energy levels
and the decay widths of kaonic hydrogen is obtained up-to-and-including
O(alpha,m_d-m_u) in QCD. It is demonstrated that, although the leading-order
corrections at O(alpha^{1/2},(m_d-m_u)^{1/2}) emerging due to the unitarity
cusp, are huge, they can be expressed solely in terms of the KN S-wave
scattering lengths. Consequently, at leading order, it is possible to derive
parameter-free modified Deser-type relations, which can be used to extract the
scattering lengths from the hadronic atom data.Comment: 9 pages, 3 postscript figures, epj style. References added, minor
revisions in the text, results unchange
Letter from the Secretary of the Treasury, transmitting, in answer to Senate resolution of December 16, 1885, statement of certain disallowed accounts, and the reasons for such disallowance.
49-1AppropriationsDisallowed Accounts. [2339] Claims, accounts, and vouchers
against the U.S. paid by disbursing officers in the Indian service.1886-6
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